I can bet this has been asked a thousand time (did a search and couldn't find exactly what I want to know). We installed our first ever packages Saturday, 04-29-17, actually our 13 year old daughter installed 2nd package and wife was photographer. The packages came from California and the queen cage just had a plug, no candy. We put in miniature marshmallow and placed queen between frame of honey and frame of drawn comb. So here's the question. What's to soon to check on queen release? I've read 3 days but that was with hard candy plug. What I've read is marshmallow takes between 12-24 hours. The reason I wanna look is I've got the new keeper bug. Went out Sunday and just watched them coming and going. Coolest thing I saw was Saturday after about 4 hours they were bringing pollen in, was such a beautiful site. My concern about being to curious is that they'll abscond. Any info would be greatly appreciated. Want what's best for the girls.
In general, make sure the queen has been released and remove the queen cage and replace the last frame on the 3rd day. Then close them up and (here's the hard part) leave them alone for a week to 10 days so that they can establish themselves as a functioning colony. At that point you will want to go in for a quick inspection just to verify that there is eggs and larvae (assuming you had some drawn comb in there).
I would guess that the bees had the chance to accept the queen during transportation, and the marshmallow was gone within the 1st day, but every package is different.
Enjoy the scene at the entrance and resist over inspecting the hive. I do remember that desire to look very well though in my first months. I am sure I prevented my first caught swarm from thriving by checking on it several times a week. Get up to a dozen hives and you can look at one or two per day all summer long. I have 18 currently, and plan to expand more this year, so I get my fill, though don't tire of it at all. Patience pays in beekeeping.